Curable hydroxy functional resin compositions containing reactive diluents

Abstract

A four-component composition is disclosed comprising a hydroxyl-bearing polymer; a liquid, amino- or hydroxyaromatic diluent having an atmospheric boiling point of about 150° C. or greater; an aminoplast or phenolic resin capable of curing the hydroxyl-bearing polymer and a strong acid catalyst for the reaction between the first and third components. Optionally, a pigment may be added to the composition.

I claim: 
     
       1. A curable composition consisting essentially of: (A) x parts by weight of a hydroxyl-bearing polymer selected from the group consisting of free hydroxyl-containing polyester, free hydroxyl-containing solid epoxy resins, and homo- and copolymers of vinyl alcohol, hydroxy alkylacrylates and α,β-unsaturated acids;   (B) from 0.10x to 0.60x parts by weight, which represents y-moles, of a liquid, hydroxyl- or amino-bearing aromatic diluent represented by the formula R(Z) b  wherein R is an aromatic radical of valence b having at least one reactive ring position located ortho or para to a Z substituent, b is an integer from 1 to 3 and Z is a --NH 2  or --OH group substituted directly on an aromatic ring of R, said diluent having an atmospheric boiling point of about 150° C. or greater;   (C) an aminoplast resin containing unreacted methylol moieties or phenolic resole resin, capable of curing component (A) to a tack-free state, present in a quantity of from (0.20x+z) to (0.50x+2.5z) parts by weight, z being equal to y multiplied by the equivalent weight of said aminoplast or phenolic resole resin; and   (D) a catalytic amount of a catalyst which catalyzes the reaction between components (A) and (C).   
     
     
       2. The composition of claim 1 wherein component (B) has an atmospheric boiling point of about 175° C. or greater. 
     
     
       3. The composition of claim 1 wherein in component (B), b is 1 or 2. 
     
     
       4. The composition of claim 1 wherein in component (B), b is 1. 
     
     
       5. The composition of claim 1 wherein component (B) is phenol or a lower alkyl-substituted derivative thereof. 
     
     
       6. The composition of claim 1 wherein component (B) is aniline or a lower alkyl-substituted derivative thereof. 
     
     
       7. The composition of claim 1 wherein in component (B), Z is a hydroxyl group. 
     
     
       8. The composition of claim 1 wherein component (C) is a melamine-formaldehyde resin. 
     
     
       9. The composition of claim 1 wherein component (C) is present in from about 0.20x+1.25z up to about 0.50x+2z, parts by weight. 
     
     
       10. The composition of claim 1 wherein from about 0.0005x to about 0.05x parts by weight of component (D) are present. 
     
     
       11. The composition of claim 1 wherein component (D) is selected from toluenesulfonic acid, sulfuric acid, ammonium salts of either, and boron trifluoride. 
     
     
       12. The composition of claim 1 wherein component (A) is a free-hydroxyl containing polyester, component (B) is phenol or a lower alkyl-substituted phenol, component (C) is hexamethoxymethyl melamine and component (D) is paratoluenesulfonic acid, sulfuric acid or the ammonium salt of either. 
     
     
       13. The composition of claim 1 which has been heated to a temperature and for a length of time sufficient to cure same to a tack-free finish. 
     
     
       14. The composition of claim 1 which further contains a pigment.